180 mm Dome Front Glass port for Outex underwater housing system.  Compatible with all Outex waterproof covers.  Dome 180 mm = opening diameter.  It is compatible with all lenses makes and models, threaded, unthreaded, hooded, fisheye, etc.  This dome works in conjunction with adaptors (threaded) and clamps (all others) to fit all lenses makes and models, so your investment is protected over time, and you can use the same glass dome for all your lenses.

Domes help correct aberrations that occur when light travels thru water as opposed to air. Domes can deliver better results compared to flat ports, and also make it easier or possible some results that flat ports would not capture. 
Bigger domes are better than smaller domes, for a number of reasons. The tradeoffs are; heavier, bulkier, pricier than smaller domes. 
Glass domes are optically superior to plastic or acrylic, and they do not scratch as easily. All of Outex ports, including its domes, are American-made glass ports. 
Both Outex glass domes are designed to fit any/all lenses thru adaptors and clamps. This design protects your investment and optimizes your usability and upgradeability over time. Our domes support both threaded, unthreaded, hooded, curved, fisheye, etc. 
Domes are ideal for split level and underwater use; While dome ports will not take anything away from your work above water, their impact or difference above the surface is irrelevant. Domes are ideal for split level, and underrater work.